Absorption refrigeration system having two stage generator

ABSTRACT

An absorption refrigeration system having a two stage generator, wherein the major components are contained in a single shell and wherein the refrigerant is released from the absorbent solution in two generating steps and steam substantially above atmospheric pressure is supplied to the first stage generator and the condensate therefrom is put in heat exchange with the absorbent in the second stage generator.

United States Patent David G. Peckham La Crosse, Wis. 773,844

Nov. 6, 1968 Apr. 13, I971 The Trane Company La Crosse, Wis.

Inventor Appl. No. Filed Patented Assignee ABSORPTION REFRIGERATIONSYSTEM HAVING TWO STAGE GENERATOR 7 Claims, 2 Drawing Figs.

US. Cl... 62/476,

Int. Cl F25b 15/06 Field of Search 62/14l, 476, 497,489,101

[56] References Cited UNITED STATES PATENTS 2,983,l l7 5/1961 Edberg etal 62/476 3,137,144 6/1964 Kaufman et a] 62/141 3,426,547 2/1969 Foster62/10 1 Primary ExaminerMartin P. Schwadron Assistant Examiner-P. D.Ferguson Attorneys-Lee E. Johnson and Arthur 0. Andersen ABSTRACT: Anabsorption refrigeration system having a two stage generator, whereinthe major components are contained in a single shell and wherein therefrigerant is released from the absorbent solution in two generatingsteps and steam substantially above atmospheric pressure is supplied tothe first stage generator and the condensate therefrom is put in heatexchange with the absorbent in the second stage generator.

Patented April 13, 1971 2 Sheets-Sheet 1 INVENTOR.

DAVID G. PECKHAM mua QWM ATTORNEY Patented April 13, 1971 3,575,012

2 Sheets-Sheet 2 FIG. 2

INVENTOR.

DAVID G. PECKHAM ATi'ORNEY ABSORPTION REFRTGERATHON SYSTEM HAVING TWOSTAGE GENERATOR it is an object of the invention to provide absorptionrefrigeration system which is more efficient in the use of heat suppliedthereto.

it is another object to provide a two stage absorption system in asingle shell in such a manner that a compact and efficient system isobtained.

it is another object to provide an absorption system which varies itsoutput according to the load imposed on the system.

Other objects and advantages of the invention will become apparent asthe specification proceeds to describe the invention with reference tothe accompanying drawings in which:

FIG. 1 is a transverse partially diagrammatic sectional view of the twostage absorption refrigeration system of my invention.

FIG. 2 is a longitudinal sectional view of the system takensubstantially on the line 2-2 of HO. 1 and having parts broken away toshow the interior construction.

In the drawings there is shown an absorption refrigeration systemcomprising a fluidtight shell enclosing a condenser 112, an evaporator14, an absorber 16, a first stage high pressure generator 18 and asecond stage low-pressure generator 20.

The shell 10 has tube sheets 11 at its ends which are in fluidcommunication with headers for conducting fluids to and from the heatexchangers in the shell as is common in the art.

The absorber 16 has a heat exchanger 22 supplied with cooling fluid froma source 24 to remove heat from the absorber l6. Source 24 may be waterwhich is evaporatively cooled by air. This cooling fluid is conducted bya conduit 26 to a heat exchanger 28 in the condenser 12. The heatexchanger 28 comprises a plurality of longitudinally extending tubes.The cooling fluid leaves the condenser through a conduit 30.

A wall 2% is secured to the sides of the shell 10 and to the tube sheetsill to separate the interior of the shell 10 into two chambers. Onechamber includes the evaporator 14 and the absorber 16 which arerelatively low in pressure. The second chamber contains a first stagehigh-pressure generator 18, a second low-pressure generator and acondenser 112, all of which have greater operating pressures than theevaporator 14 and the absorber 16.

High-pressure steam flows from a source 32 such as boiler to a heatexchanger 34 in the first stage generator 18 which is separated from thesecond stage generator by a wall 35. Heat exchanger 34 comprises aplurality of longitudinally extending tubes.

A trap 36 may be provided to pass condensate and substantially no steamfrom heat exchanger 34 back to the source 32.

Heat from the heat exchanger 34 causes the solution in the first stagegenerator to boil.

Various types of refrigerant and absorbent may be used in the presentmachine. A solution of lithium bromide as an absorbent and "water as arefrigerant is satisfactory. Other absorbents and refrigerants may beused if desired.

The term concentrated solution" as used herein means a solution which isconcentrated in absorbent.

The refrigerant vapor generated in the first stage generator lltl flowsthrough a heat exchanger 38 in the second stage generator 26. Heatexchanger 38 comprises a plurality of longitudinally extending tubes. Aflow regulating device 40 in the form of an orifice or trap regulatesthe flow of refrigerant from the heat exchanger 38 to the condenser 12.The heat from heat exchanger 38 causes the solution in the second stagegenerator and the vapor passes through a liquid eliminator 42 to thecondenser 12 in which the refrigerant vapor is condensed to a liquidwhich flows through an opening 44 to the evaporator 14. The wall 31 ofthe second stage generator is spaced from the lower portion of the wall35 of the first stage generator 18. The space between these wallscontains refrigerant vapor and therefore the transmission of heat fromthe first stage generator 18 to the second stage generator 20 iseffectively reduced to provide efficient operation. i

Absorbent solution in the absorber l6 absorbs refrigerant vapor from theevaporator 14 thus removing latent heat from the heat exchanger 46 inwhich fluid from a heat load is circulated to a heat load. Heatexchanger 46 comprises a plurality of longitudinally extending tubes.Refrigerant liquid which drips from the heat exchanger 46 is collectedby a pan 47 from which it flows through a conduit 49 to a pump 48 whichdelivers the refrigerant liquid through conduit 50 to be sprayed in theevaporator 14 through nozzles 52.

Solution from the absorber 16 flows through conduit 54, through pump 56,through low temperature heat exchanger 58, through high temperature heatexchanger 60, and through conduit 62 to first stage generator 18 inwhich it is partially concentrated.

The partially concentrated solution flows through conduit 64 from firststage generator 18 to high temperature heat exchanger 60 and thencethrough conduit 66 to second stage generator 20 in which it is furtherconcentrated. The concentrated solution from the second stage generator20 flows through conduit 68 to low temperature heat exchanger and thenthrough conduit 70 to pump 72. Dilute solution flows from absorber 16through conduit 74 to pump 72 to mix with solution flowing from conduit70 to pump 72. The solutions from conduits 70 and 74 mix at the entranceto the pump and in the pump 72. The mixed solution flows from pump 72through conduit 76 and is discharged through nozzles 78 into theabsorber l6.

CONTROL To vary the cooling capacity of the machine a steam controlvalve 80 which may be of the pneumatic-type controls the flow of steamto the heat exchanger 34 in the first stage generator. A pneumaticthermostat 32 has a sensing bulb 83 in temperature sensing relationshipwith the temperature of the chilled water leaving the evaporator 14. Thechilled water leaving the evaporator has been cooled in the evaporatorand is substantially at the same temperature. The thermostat 82 isconnected to the valve 30 to open the valve on an increase oftemperature as measured by the thermostat 82 and to close the valve 80on a decrease in temperature of the evaporator. The thermostat 62 isconnected to a source of pneumatic pressure.

To improve the efficiency of the machine as the load is reduced, asolution flow valve 34 is provided in the conduit from the discharge ofpump 56 to the heat exchanger 58. Valve 34 may be of the pneumatic typeand it is connected to receive a pneumatic pressure signal from thethermostat 82. As the temperature of the chilled water adjacent bulb 83tends to decrease the thermostat 82 opera es to close valve 84 andcirculate less solution through the system. This improves thecoefficient of performance of the machine at loads less than maximum.

Although I have described the foregoing preferred embodiment of myinvention, l contemplate that many changes may be made without departingfrom the scope or spirit of my invention and I desire to be limited onlyby the claims.

lclaim:

T. An absorption refrigeration system comprising a unitary sealedhorizontal substantially cylindrical elongated container having thereinan absorbent and a refrigerant, an elongated partition extendinglongitudinally of said container and forming with the walls of saidcontainer a low-pressure chamber and a high-pressure chamber, anabsorber and an evaporator in said low-pressure chamber, a first stagegenerator in said high-pressure chamber, a second stage generator insaid high-pressure chamber, a condenser in said high-pressure chamber,means for heating said first stage generator, means for conductingrefrigerant vapor from said first stage generator to said second stagegenerator to be condensed therein, means for conducting refrigerantvapor and refrigerant condensate from said second stage generatordirectly to said condenser without admixture prior to entry into saidcondenser, means for conducting refrigerant liquid from said condenserto said evaporator, first conduit means for conducting absorbent fromsaid first stage generator to said second stage generator, secondconduit means for conducting absorbent from said second stage generatorto said absorber, and third conduit means for conducting absorbent fromsaid absorber to said first stage generator.

2. An absorption refrigeration system according to claim 1 includingflow regulating means in said third conduit, means for regulating theflow in said third conduit means, and means responsive to thetemperature of said evaporator for adjusting said flow regulating means.

3. An absorption refrigeration system according to claim 1 wherein theabsorber is below the evaporator.

4. An absorption refrigeration system as defined in claim 1 wherein saidelongated partition has a salient portion extending between the firststage generator and the second stage generator, said salient portionbeing constructed and arranged to contain refrigerant vapor to reducethe flow of heat from the first stage generator to the second stagegenerator.

5. An absorption refrigeration system according to claim 1 wherein themeans for conducting the refrigerant received from said first stagegenerator to said condenser is a heat exchange conduit in said secondstage generator.

6. An absorption system according to claim 5 wherein said heat exchangeconduit has a flow regulating device substantially at its end whichdischarges refrigerant to said condenser, said flow regulating devicebeing constructed and arranged to restrict the flow so that the fluidpassing said valve is substantially all liquid.

7. An absorption refrigeration system comprising a unitary sealedhorizontal substantially cylindrical elongated container having thereinan absorbent and a refrigerant, an elongated partition extendinglongitudinally of said container and forming with the walls of saidcontainer a low-pressure chamber and a high-pressure chamber, anabsorber and an evaporator in said low-pressure chamber, a first stagegenerator in said high-pressure chamber, a second stage generator insaid high-pressure chamber, a condenser in said high-pressure chamber,said second stage generator being interposed horizontally between andhaving a common vertical extent with one of said first stage generatorand said condenser, means for heating said first stage generator, meansfor conducting refrigerant vapor from said first stage generator to saidsecond stage generator to be condensed therein, means for conductingrefrigerant vapor and refrigerant condensate from said second stagegenerator to said condenser, means for conducting refrigerant liquidfrom said condenser to said evaporator, first conduit means forconducting absorbent from said first stage generator to said secondstage generator, second conduit means for conducting absorbent from saidsecond stage generator to said absorber, and third conduit means forconducting absorbent from said absorber to said first stage generator.

1. An Absorption refrigeration system comprising a unitary sealedhorizontal substantially cylindrical elongated container having thereinan absorbent and a refrigerant, an elongated partition extendinglongitudinally of said container and forming with the walls of saidcontainer a low-pressure chamber and a high-pressure chamber, anabsorber and an evaporator in said lowpressure chamber, a first stagegenerator in said high-pressure chamber, a second stage generator insaid high-pressure chamber, a condenser in said high-pressure chamber,means for heating said first stage generator, means for conductingrefrigerant vapor from said first stage generator to said second stagegenerator to be condensed therein, means for conducting refrigerantvapor and refrigerant condensate from said second stage generatordirectly to said condenser without admixture prior to entry into saidcondenser, means for conducting refrigerant liquid from said condenserto said evaporator, first conduit means for conducting absorbent fromsaid first stage generator to said second stage generator, secondconduit means for conducting absorbent from said second stage generatorto said absorber, and third conduit means for conducting absorbent fromsaid absorber to said first stage generator.
 2. An absorptionrefrigeration system according to claim 1 including flow regulatingmeans in said third conduit, means for regulating the flow in said thirdconduit means, and means responsive to the temperature of saidevaporator for adjusting said flow regulating means.
 3. An absorptionrefrigeration system according to claim 1 wherein the absorber is belowthe evaporator.
 4. An absorption refrigeration system as defined inclaim 1 wherein said elongated partition has a salient portion extendingbetween the first stage generator and the second stage generator, saidsalient portion being constructed and arranged to contain refrigerantvapor to reduce the flow of heat from the first stage generator to thesecond stage generator.
 5. An absorption refrigeration system accordingto claim 1 wherein the means for conducting the refrigerant receivedfrom said first stage generator to said condenser is a heat exchangeconduit in said second stage generator.
 6. An absorption systemaccording to claim 5 wherein said heat exchange conduit has a flowregulating device substantially at its end which discharges refrigerantto said condenser, said flow regulating device being constructed andarranged to restrict the flow so that the fluid passing said valve issubstantially all liquid.
 7. An absorption refrigeration systemcomprising a unitary sealed horizontal substantially cylindricalelongated container having therein an absorbent and a refrigerant, anelongated partition extending longitudinally of said container andforming with the walls of said container a low-pressure chamber and ahigh-pressure chamber, an absorber and an evaporator in saidlow-pressure chamber, a first stage generator in said high-pressurechamber, a second stage generator in said high-pressure chamber, acondenser in said high-pressure chamber, said second stage generatorbeing interposed horizontally between and having a common verticalextent with one of said first stage generator and said condenser, meansfor heating said first stage generator, means for conducting refrigerantvapor from said first stage generator to said second stage generator tobe condensed therein, means for conducting refrigerant vapor andrefrigerant condensate from said second stage generator to saidcondenser, means for conducting refrigerant liquid from said condenserto said evaporator, first conduit means for conducting absorbent fromsaid first stage generator to said second stage generator, secondconduit means for conducting absorbent from said second stage generatorto said absorber, and third conduit means for conducting absorbent fromsaid absorber to said first stage generator.